In our Dojo, we just have white and black belts.
Wether you are 6th kyu, or 1th kyu, it doesn't matter, you wear a white belt in our Dojo. I think it's a good thing, because, what does the colour of your belt matter, really? Would it improve your skills? I think this method is used in almost all Dojos here in Belgium, but I'm not sure though.
Anyways, just my opinion on the colour of belts.
Also, I thought that coloured belts were only employed in the kids department in Japan, no?